The present invention relates generally to the field of electronics and, in particular, to the relief of Parkinson""s disease symptoms using electrical stimulation.
Parkinson""s disease is a neurodegenerative disorder that affects approximately one percent of the population over age 50 and up to two and a half percent of the population over age 70. The disease is currently of unknown origin, but appears to be the result a deficiency in dopamine (a neurotransmitter) due to the degeneration of an area of the brain known as the substantia nigra pars compacta.
Currently there is no diagnostic test for Parkinson""s disease and diagnosis is based on the presence of characteristic symptoms and elimination of other potential causes through magnetic resonance imaging (MRI). At this time there is no cure for Parkinson""s disease, only treatment to relieve the symptoms. The cardinal symptoms of Parkinson""s disease are paucity of spontaneous movements, slowness of movement, rigidity of muscle tone, and the characteristic tremor at rest. In addition, there is often a mask-like facial expression and flexed posture. Treatment with medication to relieve the symptoms of Parkinson""s disease is typically effective in the early stages of the disease""s progression. However, the medication""s effectiveness is highly variable from patient to patient. Medications also have undesirable side effects that get worse with increased dosage. As the disease progresses, it becomes more difficult to meter the medication to bring symptomatic relief while minimizing side effects. For example, some patients may be able to manage symptoms effectively with medication for 25 years. While other patients may experience intolerable side effects from increased dosage of medication within 5 years. The rate of disease progression is also highly variable.
When medication can no longer effectively manage symptoms, the patient has limited options. These include brain surgeries that lesion specific overactive areas in the brain and implanted electrodes in overactive brain areas that are controlled by a pacemaker-like device for stimulation. The stimulation appears to dampen the firing of overactive neurons providing similar symptomatic relief to the lesions. These surgical procedures are high-risk with the potential for causing hemorrhaging, blindness, or stroke.
Loss of sensing function is the major contributor to manifestation of symptoms associated with Parkinson""s disease. The loss of sensing function or inability to process sensing information leads to problems with joint position sense (observation). This in turn leads to instability in the control loops of the Basil Ganglia, causing oscillation (tremor), out of phase control signals (rigidity), and the inability to initiate a relative motor plan (akinesia) and slowed movement execution (bradykinesia). The instability results in the presentation of symptoms where a patient is unaware of a bent arm, drooping head, stooped posture, slowed gait, or lack of arm swing. As a result there is a need in the art to provide relief to patients affected with Parkinson""s disease.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for improvements in techniques to provide patients affected with Parkinson""s disease relief from the symptoms.
The above mentioned problems with treatment of the symptoms of Parkinson""s disease and other problems are addressed by embodiments of the present invention and will be understood by reading and studying the following specification.
In one embodiment, an adaptive stimulator is provided. The stimulator includes a control unit and at least one stimulation electrode coupled to an output of the control unit. The at least one stimulation electrode is adapted to provide stimulation to an area of the body of a living subject. The adaptive stimulator includes at least one sensor coupled to the control unit and adapted to be disposed external to the human body. The sensor is adapted to respond to physical stimulus and provide input to the control unit. The adaptive stimulator is adapted to selectively provide stimulation in response to the control unit.
In another embodiment, a method of adaptive stimulation is provided. The method includes receiving one or more input signals. At least one of the input signals is based on physical stimulus. The method also includes monitoring the received input signals and selectively generating one or more stimulation signals when the one or more input signals meet defined criteria. The method further includes transmitting the one or more stimulation signals to an area of the body of a living subject. The one or more stimulation signals aid in the relief of symptoms of neurological disorders.
In another embodiment, a control unit adapted to aid in the relief of symptoms of Parkinson""s disease is provided. The control unit includes an input that is adapted to couple to one or more sensors that are adapted to respond to physical stimulus. The control unit also includes a controller that is coupled to the input and a waveform generator coupled to the controller. The control unit further includes an output coupled to the controller and adapted to couple to one or more stimulation electrodes that are adapted to provide stimulation to an area on the human body. In addition, the control unit includes a stimulation voltage pulse generator coupled to the controller.